Well, greenhouse gases are gases released to the atmosphere that cause the heating of earth's atmosphere, and therefore the heating of earth's surface.
- When Earth's surface start heating whole ecosystems will suffer since temperature infleunces a lot on these.
- The ice caps in our poles will melt, rising the ocean levels and casuing possible floods.
- Water will be more scarce since it'll evaporate quicker due to increased temperatures.
Hope it helped,
BioTeacher101